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Method for controlling high-chromium ferrite heat-resistant steel austenite-based micro-deformation lath martensite structure

A technology of high-chromium ferrite and lath martensite, which is applied in heat treatment process control, manufacturing tools, heat treatment equipment, etc., can solve problems affecting equipment safety and deterioration of metal high temperature performance

Inactive Publication Date: 2010-11-17
TIANJIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The heat-resistant steel in the boiler tube works under high temperature, high pressure and steam corrosion for a long time, the structure and performance of the steel will change, which will obviously deteriorate the high temperature performance of the metal, thus affecting the safety of equipment operation

Method used

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  • Method for controlling high-chromium ferrite heat-resistant steel austenite-based micro-deformation lath martensite structure
  • Method for controlling high-chromium ferrite heat-resistant steel austenite-based micro-deformation lath martensite structure
  • Method for controlling high-chromium ferrite heat-resistant steel austenite-based micro-deformation lath martensite structure

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] The purity of the raw materials used is all higher than 99%. According to the established composition ratio in Table 2 (corresponding to T91 high-chromium ferritic heat-resistant steel), it is melted in an electric arc furnace or an induction furnace, and two processes of vacuum refining and out-of-furnace refining are carried out. Then it is hot-rolled into pipe or plate (wall thickness 1.5 cm).

[0031] Table 2 Chemical composition range of T91 high-chromium ferritic heat-resistant steel

[0032] component

Content (wt.%)

C

0.09

Si

0.03

Cr

9.1

Mo

1.1

mn

0.4

V

0.2

Nb

0.07

N

0.04

Al

0.01

[0033] (2) Micro-deformation treatment during austenitization

[0034] Put the sample into the high-frequency induction heat treatment device for treatment: first, heat it up to 1000°C at a heating rate of 50°C / min, and start loading according to the pre...

Embodiment 2

[0038] The purity of the raw materials used are all higher than 99%. According to the established composition ratio in Table 3 (corresponding to T92 high-chromium ferritic heat-resistant steel), they are smelted in an electric arc furnace or an induction furnace, and two processes of vacuum refining and out-of-furnace refining are carried out. Then it is hot-rolled into pipe or plate (wall thickness 1.5 cm).

[0039] Table 2 Chemical composition range of T92 high-chromium ferritic heat-resistant steel

[0040] component

Content (wt.%)

C

0.08

Si

0.03

[0041] component

Content (wt.%)

Cr

9.1

Mo

0.4

mn

0.4

V

0.2

Nb

0.05

N

0.04

Al

0.01

W

1.0

B

0.05

[0042] (2) Deformation treatment during austenitization

[0043] Put the sample into the high-frequency induction heat treatment device for treatment: firs...

Embodiment 3

[0047] The purity of the raw materials used is all higher than 99%. According to the established composition ratio in Table 3 (corresponding to T92 ferritic heat-resistant steel), it is melted in an electric arc furnace or an induction furnace, and two processes of vacuum refining and out-of-furnace refining are carried out, and then through Hot rolled into pipe or plate (wall thickness 1.5 cm).

[0048] (2) Micro-deformation treatment during austenitization

[0049] Put the sample into the high-frequency induction heat treatment device for treatment: firstly heat it up to 990°C at a heating rate of 80°C / min, and start loading according to the prepared stress value when the temperature reaches 700°C, and keep it constant during the subsequent heating process The stress value (1.21MPa), when the sample temperature reaches 990 ℃, it is unloaded, and at the same time, it is directly cooled by high-speed nitrogen without heat preservation, and the heating power is reduced (or even...

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Abstract

The invention relates to a method for controlling high-chromium ferrite heat-resistant steel austenite-based micro-deformation lath martensite structure, comprising: high-chromium ferrite heat-resistant steel is processed by hot rolling to be made into pipes or board with the wall thickness being not more than 6cm; sample is put into a high-frequency induction heat treatment device to be treated and then heated to be 960-1000 DEG C at the heating rate of 30-80 DEG C / min; when the temperature reaches 640-700 DEG C, loading is carried out according to the preset pressure stress value of 0.54-1.21MPa; after that, constant pressure stress value is maintained in the heating process, and unloading is carried out when the temperature of the sample reaches 960-1000 DEG C; high speed nitrogen cooling and heating power reduction are directly and simultaneously adopted for quenching cooling, and the cooling speed range is 500-6000DEG C / min. Compared with the sample which is not processed by austenite-based micro-deformation treatment, the processed high-chromium ferrite heat-resistant steel sample austenite-based lath structure is obviously thinned, the average spacing of the austenite-basedlath is thinned from 15.2 micrometers before micro-deformation to 13.5 micrometers after pressure stress micro-deformation of 0.54MPa, and the average austenite-based lath spacing corresponding to 1.21MPa is 15.0 micrometers.

Description

technical field [0001] The invention belongs to the technical field of high-chromium ferritic heat-resistant steel production, in particular to a method for controlling micro-deformed lath martensite structure in the austenitization process of high-chromium ferritic heat-resistant steel. Background technique [0002] The development of heat-resistant steel is closely related to the progress of energy, power and machinery industries. In the fields of new technology development such as thermal power generation, nuclear energy, aerospace, aviation, petroleum and chemical industries, the performance of heat-resistant steel is the key to its success, so the importance of heat-resistant steel is increasing day by day. Especially in recent years, in order to solve the increasingly prominent energy shortage and environmental pollution problems, high-efficiency super (super) critical voltage power generation has become a hot topic in the world. The parameters of thermal power genera...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21D11/00C21D8/02C21D8/10C21D1/42C21D1/18
CPCY02P10/25
Inventor 刘永长杨旭高志明刘晨曦宁保群
Owner TIANJIN UNIV